Despite overall declines in HIV transmission in the US, HIV/AIDS diagnoses among men who have sex with men (MSM) has increased from 2001-06. Venues where MSM gather continue to serve as integral locations where health and community service providers engage MSM for HIV testing, education, and prevention. Meanwhile, these providers face added challenges both with locating target populations and in translating interventions to non-traditional settings (e.g., Internet). While there have been studies conducted within venues where MSM meet sex partners, there is little cross-venue analyses, thus little contextualization of how venue-level characteristics (e.g., alcohol/drugs in bars, anonymous chat online, dark/quiet spaces in bathhouses) can create social norms that can significantly impact how MSM negotiate HIV-associated risk behavior (e.g., serostatus disclosure, condom use). Consistent with the SC2 mechanism, the proposed pilot study will use probability-based recruitment methods to identify and longitudinally follow (for 6 months) three diverse samples of sexually active MSM (N = 150): one sample recruited via bathhouses (n = 50), one recruited at bars (n = 50), and one recruited off the Internet (n = 50). Measures will be both qualitative and quantitative in nature. In addition to identifying venue-level patterns and the prevalence of HIV-associated risk behavior (i.e., sexual behavior specific to the venues where partners were met), this study will focus on identifying venue- level characteristics (e.g., lighting; sound; perceived social norms around unsafe sex, drug, or alcohol use; perception of anonymity) in an effort to determine their impact on participant's sexual behavior and sexual decision making. Additional attention will be paid to intersecting roles that alcohol and club drugs may play in venues and subsequent sexual behaviors with partners met via venues. Finally, using a longitudinal design, this study will track changes in participant's sexual behaviors, substance use behaviors, and venue frequenting to identify connections between venue-specific partners and subsequent sexual behaviors, HIV-risk, drug, and alcohol use. Consistent with the SC2 mechanism, this pilot study will serve as the basis for developing and testing a venue-based intervention to reduce HIV transmission risks among MSM. Given the study's findings, and the SC2 mechanism's objective (long-term development of a new line of research), this will warrant developing PI- initiated R34 and/or R01 grants. To accomplish these goals, Dr. Christian Grov (PI) has partnered with Dr. Jeffrey Parsons (Mentor), who is an accomplished NIH-funded investigator with expertise in translating formative research findings into interventions. Together, they have created a comprehensive PI development plan that is equipped with a 4-phase timeline and measurable indicators of success. PUBLIC HEALTH RELEVANCE: The findings of this study will facilitate a more nuanced understanding of HIV-associated risk behaviors contextualized within social atmospheres (venues) that men who have sex with men (MSM) encounter their sex partners. These data will, in turn, inform venue-based HIV prevention and intervention efforts, and treatments designed to reduce MSM's HIV associated risk behaviors. Consistent with the SC2 mechanism, the pilot data generated from this study will serve as the basis for developing and testing a venue-based intervention to reduce HIV transmission risks among MSM.